Crop Factor Calculator
Crop factor describes how much smaller a camera sensor is compared to a full frame 35mm sensor (36x24mm). It is calculated by dividing the diagonal of a full frame sensor (43.27mm) by the diagonal of the sensor in question. A Canon APS-C sensor (22.3x14.9mm) has a diagonal of about 26.8mm, giving a crop factor of approximately 1.6. When you mount a lens on a crop sensor body, the sensor records only the central portion of the image circle the lens projects. The result looks the same as if you had used a longer focal length lens on a full frame body. Multiply the actual lens focal length by the crop factor to get the full frame equivalent focal length, which tells you the field of view you can expect. A 50mm lens on a 1.6x crop body gives the same angle of view as an 80mm lens on full frame. Crop factor also affects angle of view: angle of view (horizontal) equals 2 times the arctangent of the sensor width divided by twice the focal length. This calculator handles preset sensor formats and custom dimensions. Enter your sensor size and lens focal length to see the crop factor, equivalent focal length, and angle of view on both the crop and full frame.
Crop factor: 1.60, equivalent focal length: 80.00 mm on full frame.
How crop factor is calculated
Crop factor is the ratio of the full frame sensor diagonal to the sensor diagonal of the camera in question. The full frame sensor (36x24mm) has a diagonal of exactly sqrt(36^2 + 24^2) = sqrt(1296 + 576) = sqrt(1872) = 43.27mm.
Sensor diagonal (mm) = sqrt(width^2 + height^2)
Crop factor = 43.27 / sensor diagonal
Full frame equivalent focal length (mm) = actual focal length x crop factor
Horizontal angle of view = 2 x arctan(sensor width / (2 x focal length))
Worked example
Canon APS-C sensor (22.3x14.9mm), 50mm lens:
- Diagonal = sqrt(22.3^2 + 14.9^2) = sqrt(497.29 + 222.01) = sqrt(719.30) = 26.82mm
- Crop factor = 43.27 / 26.82 = 1.61
- Full frame equivalent focal length = 50 x 1.61 = 80.7mm
- Horizontal angle of view = 2 x arctan(22.3 / (2 x 50)) = 2 x arctan(0.223) = approximately 24.9 degrees on the crop sensor
- Full frame horizontal angle of view at 80mm = 2 x arctan(36 / 160) = approximately 24.9 degrees (confirming equivalence)
Common sensor sizes and crop factors
| Sensor format | Dimensions (mm) | Diagonal (mm) | Crop factor | Typical cameras |
|---|---|---|---|---|
| Full frame (35mm) | 36 x 24 | 43.27 | 1.00 | Sony A7, Canon EOS R5, Nikon Z6 |
| APS-H | 28.7 x 19 | 34.36 | 1.26 | Canon 1D series (discontinued) |
| APS-C (Canon) | 22.3 x 14.9 | 26.82 | 1.61 | Canon EOS 90D, R7, R10 |
| APS-C (Nikon/Sony/Fuji) | 23.5 x 15.6 | 28.21 | 1.53 | Nikon Z50, Sony A6700, Fujifilm X-T5 |
| Micro Four Thirds | 17.3 x 13 | 21.64 | 2.00 | Olympus OM-5, Panasonic G9 II |
| 1-inch | 13.2 x 8.8 | 15.86 | 2.73 | Sony RX100 VII, Nikon Z30 (compact) |
| 1/1.7-inch | 7.6 x 5.7 | 9.50 | 4.55 | Compact cameras, older phones |
What crop factor means in practice
The most practical consequence of crop factor is the change in effective field of view. A 50mm lens is considered a "standard" lens on full frame because its angle of view (about 47 degrees horizontal) roughly matches human peripheral vision. On a 1.6x APS-C body, the same lens frames like an 80mm portrait lens. On a Micro Four Thirds body (2.0x), it frames like a 100mm short telephoto.
This can be advantageous (wildlife and sports photographers on crop bodies effectively get more reach from telephoto lenses) or a drawback (wide-angle lenses become less wide). A 24mm wide-angle on full frame frames like a 38mm moderate wide on APS-C (1.6x), requiring a 15mm lens to match the same field of view on the crop sensor.
Crop factor does not change the physical optics of the lens. The focal length, maximum aperture, and light-gathering ability remain constant. What changes is which portion of the projected image circle the sensor captures.
Crop factor calculator: frequently asked questions
What is crop factor?
Crop factor is the ratio of the diagonal of a full frame 35mm sensor (43.27mm) to the diagonal of a smaller sensor. A crop factor of 1.5 means the sensor diagonal is 1.5 times smaller than full frame. When you use a lens designed for full frame on a smaller sensor, the sensor captures only the central portion of the image circle, effectively multiplying the apparent focal length by the crop factor. A 50mm lens on an APS-C body with a 1.5x crop factor gives the same field of view as a 75mm lens on a full frame body.
Does crop factor affect depth of field?
Yes, indirectly. Crop factor itself does not change the optics of a lens. However, to achieve the same field of view on a crop sensor body you use a shorter focal length lens or stand further from the subject. A shorter focal length at the same aperture and subject distance produces greater depth of field. To match the field of view and depth of field of a full frame camera, you would need to open the aperture by the same factor as the crop: for example, a 35mm f/1.4 on APS-C (1.5x) approximates the field of view of 52mm on full frame but gives about 1 stop more depth of field than 52mm f/1.4 on full frame.
Which cameras use APS-C sensors?
APS-C is the most common crop sensor format among interchangeable-lens cameras. Canon APS-C bodies (such as the EOS 90D, R7, and R10) have a 22.3x14.9mm sensor with a 1.6x crop factor. Nikon APS-C bodies (such as the Z30, Z50, and Z fc) and Sony APS-C bodies (such as the A6700 and ZV-E10) use a slightly larger 23.5x15.6mm sensor with approximately a 1.5x crop factor. Fujifilm X-series cameras also use an APS-C sensor at 23.5x15.7mm.
Is a bigger sensor always better?
Not necessarily. Larger sensors generally capture more light per pixel, which can improve dynamic range and low-light performance, and they allow shallower depth of field at a given field of view. However, cameras with larger sensors are typically larger, heavier, and more expensive, as are their lenses. Smaller sensors such as Micro Four Thirds offer a compact, lighter system that is well suited to travel and video. The best sensor size depends on your use case, budget, and how you will use the images.
How does crop factor affect low-light performance?
A larger sensor with larger photosites (individual light-collecting elements) captures more light and tends to produce less noise at high ISO settings. Full frame sensors typically outperform APS-C in low light, and APS-C typically outperforms Micro Four Thirds, all else being equal. However, sensor generation matters: a modern APS-C sensor may outperform an older full frame sensor. Lens aperture is also important: a fast f/1.4 lens on a crop sensor can gather comparable total light to an f/2.0 lens on full frame, partly offsetting the sensor size disadvantage.
Sources
- Wikipedia: Crop factor.
- Imaging Resource: What is crop factor and why should I care?
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology. General information only.